title: Treatment response assessment of radiofrequency ablation for hepatocellular carcinoma: usefulness of virtual CT sonography with magnetic navigation.
abstract: OBJECTIVE
  Virtual CT sonography using magnetic navigation provides cross sectional images of CT volume data corresponding to the angle of the transducer in the magnetic field in real-time. The purpose of this study was to clarify the value of this virtual CT sonography for treatment response of radiofrequency ablation for hepatocellular carcinoma.
  
  
  METHODS
  Sixty-one patients with 88 HCCs measuring 0.5-1.3 cm (mean±SD, 1.0±0.3 cm) were treated by radiofrequency ablation. For early treatment response, dynamic CT was performed 1-5 days (median, 2 days). We compared early treatment response between axial CT images and multi-angle CT images using virtual CT sonography.
  
  
  RESULTS
  Residual tumor stains on axial CT images and multi-angle CT images were detected in 11.4% (10/88) and 13.6% (12/88) after the first session of RFA, respectively (P=0.65). Two patients were diagnosed as showing hyperemia enhancement after the initial radiofrequency ablation on axial CT images and showed local tumor progression shortly because of unnoticed residual tumors. Only virtual CT sonography with magnetic navigation retrospectively showed the residual tumor as circular enhancement. In safety margin analysis, 10 patients were excluded because of residual tumors. The safety margin more than 5 mm by virtual CT sonographic images and transverse CT images were determined in 71.8% (56/78) and 82.1% (64/78), respectively (P=0.13). The safety margin should be overestimated on axial CT images in 8 nodules.
  
  
  CONCLUSIONS
  Virtual CT sonography with magnetic navigation was useful in evaluating the treatment response of radiofrequency ablation therapy for hepatocellular carcinoma.
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Internal Medicine, Kinki University School of Medicine, 377-2 Ohno-Higashi, Osaka-Sayama 589-8511, Japan. minkun@med.kindai.ac.jp
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Minami
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kitai
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Kudo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging* / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D016009:Chi-Square Distribution; D003287:Contrast Media; D018450:Disease Progression; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery*; D008280:Magnetics; D008297:Male; D008875:Middle Aged; D018365:Neoplasm, Residual / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome; D014463:Ultrasonography / Q000379:methods*; D014584:User-Computer Interface
chemical_list: D003287:Contrast Media